JPH04103209U - 4 cycle engine - Google Patents

Abstract

(57) [Summary] (with amendments) [Purpose] To create a 4-cycle engine that is low cost, lightweight, compact, simple in structure, and highly reliable without using conventional screw gears using a new camshaft drive structure. It is to provide. [Structure] In a 4-cycle engine having a cantilevered crankshaft 20, the output shaft portion 21a of the cantilevered crankshaft
is supported by bearings 24a and 24b provided at two locations, and a guide section is formed at one location between the two bearings in a shape that goes around the output shaft twice and returns to its original position. This four-stroke engine is characterized in that an interlocking mechanism 28 guided by a guide portion is provided, and the interlocking mechanism opens and closes the intake and exhaust valve mechanisms of the four-stroke engine.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a small, general-purpose four-stroke engine with a simple structure.

0002

[Prior art and its problems]

In general, small general-purpose 4-stroke engines are low cost, lightweight and compact. It is desired that

0003 In order to satisfy such requirements, the prior art of Utility Model Application Publication No. 58-66105 has been used. has already been developed.

0004 This prior art uses a cantilevered crankshaft, but the cam for driving the valve train The shaft is placed perpendicular to the crankshaft, and the power from the crankshaft is transferred to the camshaft using a screw gear. is being communicated to.

[0005] However, a camshaft and a bearing for the camshaft are required, and in order to accommodate these The problem is that the engine becomes larger due to the space required.

[0006] In addition, the camshaft and screw gears increase costs, and the wear of the screw gears reduces reliability. However, the problem is that the structure becomes even more complex.

[0007]

[Purpose of invention]

This invention uses a new camshaft drive structure to eliminate the need for conventional screw gears and is low-cost. The engine is lightweight, compact, has a simple structure, and has a highly reliable 4-stroke engine. is intended to provide.

[0008]

[Structure of the idea]

The four-stroke engine of this invention is a four-stroke engine with a cantilevered crankshaft. In the engine, the output shaft of the cantilevered crankshaft is supported by bearings provided at two locations, There is a guide in one place between both bearings that is shaped so that it goes around the output shaft twice and returns to its original position. A guide part is formed, and an interlocking mechanism guided by this guide part is provided, and the interlocking mechanism can perform 4 cycles. The system is characterized by an air intake and exhaust valve mechanism that opens and closes the engine. Furthermore, the guide portion is composed of a sash-like groove, and the bottom surface of the groove is a cam surface. It is something that exists.

[0009]

[Effect]

The interlocking mechanism is driven by the guide part, and the intake and exhaust valves are opened and closed via the interlocking mechanism. . The output shaft is supported by two bearings, so the shaft center does not act on the crankshaft. It is supported so that it does not become eccentric due to the explosive force of the engine.

0010

【Example】

(1) First example When this invention is applied to an overhead valve type small general-purpose 4-stroke engine, In FIG. 1, which shows the engine block, 10 is an engine block. engine block 10 The cylinder 12, crankcase 14, side cover 16, etc. are integrally formed. ing. The lower right end of the engine block 10 in the figure is cut diagonally and is open. and is sealed with an oil pan 10a.

[0011] A piston 18 is slidably provided in the cylinder 12, and the piston 18 is slidably provided in the cylinder 12. A cantilevered crankshaft 20 is rotatably supported on 14. piston 18 and piece The holding crankshaft 20 is connected by a connecting rod 22.

0012 The cantilevered crankshaft 20 includes an output shaft portion 21a, a crank web 21b, and a crank pin. It is an integrally forged product consisting of a crank pin 21c, and a side plate 2 is attached to the crank pin 21c. 1d is attached with a bolt 21e. The output shaft portions 21a are separated by a predetermined interval. It is pivotally supported by the crankcase 14 by two bearings 24a and 24b. bear The ring 24b has a larger diameter than the bearing 24a and acts on the cantilevered crankshaft 20. The large-diameter bearing 24b absorbs the explosive force of the engine, and the bearing This makes it easier to attach and detach the plugs 24a and 24b and press-fit the output shaft portion 21a. It has been taken into consideration. 24c is an oil seal.

[0013] The output shaft portion 21a between the bearing 24a and the bearing 24b has an intake valve The guide groove 26a (guide portion) and the guide groove 26b (guide portion) for the exhaust valve are adjacent to each other. It is formed by That is, the guide portion is located at one location between both bearings 24a and 24b. It is formed.

[0014] The guide groove 26a goes around the output shaft portion 21a of the cantilevered crankshaft 20 twice and returns to its original position. It is formed in the shape of a sash (Fig. 4). Also, the bottom surface of the guide groove 26a is a cam surface. The output shaft portion 21a has a peak portion 27 extending outward in the radial direction. a (Fig. 1) is provided at one location. The position of the mountain portion 27a in the circumferential direction is the same as that of the intake valve. The crank angle position corresponds to the valve opening timing.

[0015] A slider 28 (interlocking mechanism) for an intake valve is connected to the guide groove 26a. sliding As shown in FIG. 2, the child 28 has a sliding shaft portion 29 formed in the shape of a vertically long rod. a and forms part of the crankcase 14 of the engine block 10 It is rotatably and vertically slidably supported by a supporting wall portion 15a. Slider A horizontal arm portion 29 is provided at the lower end of the output shaft portion 28 and extends to approximately the upper edge portion of the output shaft portion 21a. b is formed, and the horizontal arm portion 29b slides around the vertical axis of the slider 28. It can swing freely together with the child 28.

[0016] A ball 30 is rotatably supported at the tip of the horizontal arm portion 29b. The ball 30 is engaged with the guide groove 26a.

[0017] An upper end portion of the sliding shaft portion 29a projects above the support wall portion 15a, and this upper end portion A spherical seat surface 29c is formed in the seat. Inside the side cover 16 is the spherical seat surface 29c. A spherical end 33a of the push rod 32 disposed in the push rod 32 is rotatably fitted therein.

[0018] The upper end of this push rod 32 extends above the cylinder 12 and is connected to the rocker arm. It is pressed into contact with one end of the arm 34 from below. The rocker arm 34 is attached to the cylinder 12. The other end of the rocker arm 34 is supported swingably at the upper part of the intake valve 36. The intake valve 36 is opened by pressing against the valve rod 37a.

[0019] The exhaust valve slider 31 has a similar structure to the intake valve slider 28. Slider 3 The peak 27b of the guide groove 26b with which 1 is engaged corresponds to the opening timing of the exhaust valve. The crank angle position is approximately 180 degrees apart from the peak 27a. has been done.

[0020] A push rod 38 similar to the push rod 32 is also supported at the upper end of the slider 31. The push rod 38 connects the exhaust valve (not shown) as well as the intake valve 36. The valve is now open. In addition, 40 in FIG. 1 is a rocker cover.

[0021] Next, the effect will be explained. When the cantilevered crankshaft 20 rotates, for example, the intake valve 36 The ball 30 is guided by the guide groove 26a, and the cantilever crankshaft 20 rotates twice. During this time, the ball 30 comes into sliding contact with the entire circumference of the guide groove 26a, and is brought into contact with the crest 27a. One lift operation is applied to the intake valve 36. Also, the horizontal arm portion 29b is While the holding crankshaft 20 rotates twice, it swings from the position shown in Fig. 1 once to the left and right, and slides. The sliding shaft portion 29a of the mover 28 also rotates, but the spherical end portion 33a of the push rod 32 is rotatably supported on the spherical seat surface 29c, so that the push by the slider 28 There is no possibility that the upward movement of the rod 32 will be hindered.

[0022] The same applies to the push rod 38 for the exhaust valve.

[0023] The crankcase 14 of the engine block 10 has one crank web 21b. Since it is only necessary to accommodate the cantilevered crankshaft 20, the size is reduced, and the right end in the figure It is possible to cut it diagonally and cover it with the oil pan 10a.

[0024] In addition, the crankcase 14 covers the output shaft portion 21a, and bears 24a, 24b. Since the output shaft portion 21a is supported in two places, it is less likely to vibrate than a normal shaped crankshaft. The output shaft portion 21a of the cantilevered crankshaft 20, which undergoes a large amount of movement, is prevented from being eccentric. I support it. Therefore, guide grooves 26a and 26b were formed in the output shaft portion 21a. Even if the rotation centers of the guide grooves 26a and 26b do not change, the slider 28 and the pusher The amount of lift given to the intake valve 36 and the exhaust valve through the rod 32 is accurate. Ru.

[0025] Furthermore, since the side cover 16 is placed above the crankcase 14, Use the dead space above the crankcase 14 to install the pushrod. A space can be formed to allow the doors 32 and 38 to pass, and the entire engine can be I'm keeping it to myself.

[0026] (2) Second embodiment A second embodiment of the present invention will be described with reference to FIG. Note that in Figure 5, the same Parts with one numeral indicate the same or equivalent parts.

[0027] This second embodiment is a case where the present invention is applied to a side valve type engine, and is shown in Fig. 5. The intake valve 36 and the exhaust valve (not shown) are arranged adjacent to each other in a direction perpendicular to the page. .

[0028] The valve stem 37a of the intake valve 36 slidably passes through the support wall 15a and extends downward. It's growing. The lower end of the valve stem 37a is in pressure contact with an interlocking mechanism 44, which will be described in detail later. , the interlocking mechanism 44 is guided by one guide groove 48 (guide portion) and connects the intake valve 36 and It is designed to open and close the exhaust valve and exhaust valve. The guide groove 48 is connected to the metal bearing 46. It is formed on the output shaft portion 21a between the rings 24b.

[0029] As shown in FIG. 6, this interlocking mechanism 44 is composed of a bell crank 50 and a support shaft 52. has been done. The bell crank 50 moves in the axial direction on a support shaft 52 parallel to the output shaft portion 21a. It is fitted so that it can freely swing around the axis. Downward arm part of bell crank 50 51a has its lower end engaged with the guide groove 48 via the ball 30. . The tip of the horizontal arm portion 51b of each bell crank 50 is connected to each valve rod 37a, 37. b are in contact with the lower end portions from below.

[0030] As in the case of FIG. 4, the guide groove 48 goes around the output shaft portion 21a twice and returns to its original position. It is shaped like a sash that goes back to . In addition, the bottom surface of the guide groove 48 is a cam surface, There are peaks 49a (Fig. 5) at crank angle positions corresponding to the intake timing and exhaust timing. It is formed.

[0031] In the engine shown in FIG. 5, each bell crank is rotated while the cantilever crankshaft 20 rotates twice. The shaft 50 is rotated 52 times by the cam action of the peak 49a on the support shaft at each intake period and exhaust period. The intake valve 36 and the exhaust valve are swung to give a lift action to the intake valve 36 and the exhaust valve.

[0032]

[Effect of the idea]

As explained above, the four-stroke engine of the present invention has a cantilevered crankshaft. In a 4-cycle engine, the output shaft of the cantilevered crankshaft is installed in two locations. The output shaft is supported by the bearing part, and the output shaft part is rotated twice and returned to the original position at one place between the two bearing parts. A guide portion having a shape such as that shown in FIG. Since the interlocking mechanism is used to open and close the intake and exhaust valve mechanism of a 4-cycle engine, A small general-purpose engine having a cantilevered crankshaft 20 has the following effects.

[0033] Since the camshaft can be eliminated, significant cost reductions can be achieved and energy savings can be achieved. The engine can be made more compact.

[0034] Machining time is reduced because there is no need to machine gears or sprockets for camshaft reduction. It can be made shorter.

[0035] Machine noise can be reduced.

[0036] Compared to a normal both-end supported crankshaft, the engine's explosive force is applied to the output shaft portion 21a. When using a cantilevered crankshaft 20 that is strongly worked and causes the output shaft portion 21a to vibrate greatly, Even if the Clamp the output shaft portion 21a in a state where the rotation axis of the output shaft portion 21a is not eccentric. It can be pivoted to the case 14. Therefore, the bearing 24a and the bearing Guide grooves 26a and 26b for driving intake and exhaust valves are provided in the output shaft portion 21a between 24b and 24b. The axis of the output shaft portion 21a does not become eccentric even when the intake and exhaust valves open and close. It is possible to accurately exhibit the period and lift amount according to the set characteristics. Also de The shaft part between the bearings 24a and 24b and the space above the same part that tends to become a dead space. Since the space can be used effectively, the entire engine can be made more compact.

[0037]

[Another example]

(1) The present invention is not limited to the above two embodiments, and the combination of valve arrangement and interlocking mechanism is It can be selected arbitrarily. (2) The guide portion is not limited to the guide grooves 26a, 26b, and 48 as in the embodiment. , it may also be a guide rail with a convex surface.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a four-stroke engine according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a slider.

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2;

FIG. 4 is a developed view of the guide section.

FIG. 5 is a longitudinal sectional view showing a 4-stroke engine according to a second embodiment of the present invention.

6 is a partial cross-sectional view taken along line VI-VI in FIG. 5. FIG.

[Explanation of symbols]

10 Engine block 20 Cantilever crankshaft 21a Output shaft part 21b crank web 21c crank pin 24a, 24b bearing 26a, 26b guide groove 28, 31 Slider 32, 38 push rod 36 Intake valve 44 Interlocking mechanism

Claims (2)

[Scope of utility model registration request] Claim 1: In a four-cycle engine having a cantilevered crankshaft, the output shaft portion of the cantilevered crankshaft is supported by bearings provided at two locations, and one location between the two bearings is provided with an output shaft portion of the cantilevered crankshaft.
A guide part is formed in a shape that goes around the output shaft part twice and returns to the original position, and an interlocking mechanism guided by this guide part is provided, and the interlocking mechanism opens and closes the intake and exhaust valve mechanism of a 4-stroke engine. A 4-cycle engine characterized by the following features: 2. The four-stroke engine according to claim 1, wherein the guide portion comprises a sash-like groove, and a bottom surface of the groove is a cam surface.